Two types of bone formation

• Intramembranous bone formation:

1. From mesenchymal cells
2. No cartilage formation
3. Forms primary spongy bone, spicules, lacunae, osteocytes, skull

• Endochondral bone formation:

1. From hyaline cartilage
2. Forms long bones, vertebrae, pelvis bones
3. Epiphyseal plate: reserve zone, zone of proliferation, zone of hypertrophy, bone marrow.